It’s Citrus Season by Katie Walter

Anyone with a citrus tree or a friend with one is inundated with lemons and oranges now. Bags of lemons pass from hand to hand for use in lemon curd, limoncello liqueur, lemon meringue pie or just juice for the freezer. Oranges make fabulous fresh juice, putting the store-bought product to shame.

San Joaquin County hosts one of the best climates for homegrown citrus. Except for the occasional freezing nights in December and January when your tree may need a sheet or blanket for protection, citrus love our climate. If the tree is near your home, say against the house or in a corner surrounded by the house on two sides, warmth from the house will likely provide all the protection it needs.

Cold weather recently in Florida was devastating for the commercial citrus crop there. Even occasional freezes are incompatible with large-scale citrus production. A drive to Los Angeles on Interstate 5 shows where oranges and other citrus do well in the Central Valley. The orchards, on the left as you drive south, are a few hundred feet above the valley floor and out of the worst fog and cold. Microclimates matter.

If you are considering taking advantage of our climate and planting a tree or two, keep in mind that oranges and lemons are just the beginning. Limes provide a tart tingle to many drinks and make a delicious soufflé. Grapefruit are yummy for breakfast or in salads. Juice from key limes are the critical ingredient in key lime pie.

Bitter oranges are used for traditional orange marmalade. Kumquats are tiny fruit that look lovely on the tree. They have a sweet rind and sour flesh and make excellent marmalade. The well-named, dark-red blood orange makes fantastic juice. Or you might get exotic and plant the many-fingered Buddha’s hand.

Lemons are probably the most frequently planted citrus here because they are such a versatile fruit. The firm, oval “Eureka” lemon is the one most often found in the grocery store. The round, soft, thin-skinned “Meyer” is the variety typically planted in our backyards and is likely the one in most of the bags being passed around. The juice of the Meyer is much sweeter than the Eureka’s, which makes sense when you learn that the Meyer is a cross between a lemon and either a mandarin orange or a common orange. A very happy accident created our delicious Meyer lemons!

Nurseries and big-box stores are full of citrus trees in pots right now. Full-sized varieties give you lots of fruit but be careful about height. You want to be able to pick the fruit when the tree is fully grown. A dwarf or semi-dwarf variety is just the ticket for easy-to-pick fruit or if you are short on space. Labels on the potted trees are usually excellent for providing information on variety, anticipated size, and cold tolerance. After the tree is home and in the ground, cut it back by about one-third of its height. With luck, the nursery person will be knowledgeable about how much to cut your new tree back.

Don’t expect to get a real crop for two to three years. Don’t let any fruit mature during that period. Pick them early and dispose of them. It takes a few years for the tree to settle in and establish a good root structure. Only then can the tree concentrate on producing high-quality fruit. Bon appetit!

Now for some bad news. You may have heard about the Asian citrus psyllid (pronounced “sillud”) and citrus greening disease, which the psyllid causes. The disease can kill a citrus tree in as little as five years. There is no known cure, although scientists are busy searching for one.

The psyllid is a tiny insect that feeds on all varieties of citrus, in commercial orchards and backyards. It damages the tree by feeding on new leaf growth and by introducing to the tree the bacterium that causes citrus greening disease, also known as huanglongbing. The psyllid first showed up in Asia and had made its way to Florida by 1998. By 2001, the insect was in 31 Florida counties and had spread to Texas. In 2008, the psyllid was Southern California. Today it is widespread in the Central Valley. A diseased tree declines in health and produces bitter, green, misshaped fruit until it dies.

The California Department of Food and Agriculture has undertaken an extensive monitoring program to track the distribution of the insect and disease. Program personnel regularly check yellow sticky traps for the psyllid, in both residential areas and commercial citrus groves, in locations where the psyllid may be spreading. The program also includes frequent testing of psyllids and leaf samples for the presence of the bacterium.

Damaged fruit is safe to eat and not harmful to humans. If you think a tree on your property is affected, do not remove it or any plant materials from the area and call the Department of Food and Agriculture’s Pest Hotline at 1-800-491-1899. For more information on the Asian citrus psyllid and huanglongbing disease, visit:

For gardening-related questions, call the UC Master Gardener office at 209-953-6112, or use our website:

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